This application explores the formation of expectation for visual events in infants. Visual fixations are recorded to index the presence of anticipation and facilitated reactions. Two experiments are proposed with human infants 5- and 9-months of age. The first experiment is designed to explore interactions of age and picture sequence complexity on infants' ability to form expectations. The second study is designed to discover if infants deep track of the number of pictures appearing on a side to predict future stimulus position. The method employs infrared corneal-reflection video recording of fixation sequences. Through an analysis of infants' scanning records and derived eye movement parameters, inferences will be drawn about whether a baby has anticipated the occurrence of an event before it occurs. A second index of expectation is facilitated reactions. By examining the babies' latencies to fixate predictable but nonanticipated events (in comparison to control conditions), it will be determined whether the baby has developed an expectation for those events. The long-term objectives of this application are to establish the visual expectation paradigm as a viable and useful research tool for studying basic issues of infant cognitive and perceptual development, number perception, and the development of future oriented behavior. The specific aims include developing the apparatus and procedure necessary for undertaking studies of expectation with infants older than 4 months of age and carrying out two studies of visual expectation with 5- and 9-month-old infants. The data will be used for understanding the development of expectation for various levels of predictability in a normal infant population and will serve as a foundational study for the construction of a fine-grained sequence of tasks of increasing difficulty.